SSCP Exam: Understanding IP Protocol Field

The IP Protocol Field: Exploring Data Types

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Question

The IP header contains a protocol field.

If this field contains the value of 51, what type of data is contained within the ip datagram?

Answers

Explanations

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A. B. C. D.

B.

TCP has the value of 6 - UDP has the value of 17 - ICMP has the value of 1 - Reference: SANS http://www.sans.org/resources/tcpip.pdf?ref=3871

The IP header is a part of the Internet Protocol (IP) suite that is used for transmitting data over the internet. It contains information about the source and destination of the IP packet, as well as other information needed for proper routing.

The protocol field in the IP header is used to identify the protocol that is being used for the data within the IP datagram. The protocol field is a single byte (8 bits) that contains a number that corresponds to a particular protocol.

In this case, the question is asking what type of data is contained within the IP datagram if the protocol field contains the value of 51.

The answer is B, Authentication Header (AH). The value of 51 in the protocol field corresponds to the Authentication Header (AH) protocol, which is used to provide authentication and integrity protection for IP datagrams. AH is one of two protocols used in IPsec (the other being the Encapsulating Security Payload, or ESP), which is a suite of protocols used to secure IP communications.

To summarize, if the protocol field in the IP header contains the value of 51, the data within the IP datagram is using the Authentication Header (AH) protocol for authentication and integrity protection.